29

G30

of the retroductive hypothesis. The word "retroductive,"
however, is surplusage; for every hypothesis, however arbitrary, is
suggested by something observed, whether externally or internally;
and such suggestion is, from a purely logical point of view,
retroduction. Consequently, this second stage of inquiry embraces
all deduction, all necessary inference, including necessary
inference concerning probability. Thus, if the odds are 3 to 1 that
that if the sum of the numbers uppermost in one throw of a pair of
dice if not divisible by 3 will not be 7, and if the odds are 2 to 1 that